The equine hoof is a complex composite structure composed of soft (low sulfur) keratins and hard(high sulfur), tubular keratins embedded in a protein-keratin matrix. These components are structurally aligned in the hoof to absorb and dissipate the shock associated with the impact of a hoof with a surface, especially during running.
Keratin is a key component and imparts strength and flexibility to the hoof. The keratin must be maintained in a flexible state and kept from drying out and becoming brittle as it does in a condition called "dry hoof". This condition increases the tendency of the hoof to crack or break. If the hoof cracks or breaks it can result in injury to the animal. The key to keeping the keratin flexible is to keep it water balanced.
In the case of the horse, blood circulating through the hoof supplies sufficient nourishment and moisture to the hoof to maintain the keratin water balanced. Blood circulation through the hoof is lowered when the horse is standing still compared to circulation when the horse is walking and running because there are physical structures in the hoof that flex in response to the application and release to the horse's weight and thereby assist in the pumping of blood through the veins and arteries of the horse's leg. These physical structures include: the wall keratin and matrix protein which absorb and dissipate the shock of impact during running, a frog and sole which are keratinous and are located in the undersole of the hoof and which flex in response to walking and running, heel bulbs(also keratinous) which are located in the heel at the back of the horse's hoof and which flex outwardly when the horse's hoof strikes the ground, and the digital cushion, a vascularized area between the heel bulbs and the frog which compresses during walking and running. These structures cooperate to assist in circulating blood in the equine hoof in the following manner: when the hoof strikes the ground the keratin tubules and matrix absorb and transmit shock to the heel which expands outwardly, the frog and the sole expand downward, and the digital cushion compresses. This expansion and compression pumps venous blood, in the hoof, up the leg. Release of hoof from the surface returns the structures of the hoof to their rest position and arterial blood flows into the hoof. This pumping action increases the flow of blood through the hoof and thereby assures that nutrients and moisture is provided to the hoof which is vital to maintaining keratin flexibility.
When the keratin and matrix of the hoof become brittle, the heel bulb, frog, and wall expansion is diminished because the keratin does not flex as it normally does and has a tendency to crack or split. Additionally, a dry hoof does not dissipate the impact of the hoof's striking the ground in running as effectively as a natural, water balanced, flexible hoof. This condition, if untreated, can lead to numerous problems.
The healthy equine hoof has a relatively non-sticky surface which retards the adherence of dirt. This condition is augmented by the periople, which is a region of the hoof beginning at the coronary band and extending some variable distance downward. The function of the periople is to secrete a complex lipid film that spreads over the surface of the hoof to act as a moisture barrier. This lipid coating is also slippery and aids in preventing the adherence of dirt and foreign matter that might absorb the moisture from the hoof.
In their natural environment the horse is not immobilized for any duration and the hoof is not deprived of nourishment and moisture for an extended time. The situation is different for domesticated, stabled horses. When a horse is confined for an extended period of time the amount of blood circulating through its hoof is less than when the horse is moving. This results in less moisture passing to the keratin of the hoof. Additionally, a stall containing sawdust or other absorbant materials sets up a drying environment that dries the hoof's moisture and oil.
Other conditions contributing to the dry hoof problem include the rasping of the periople by the farrier, painting the hoof with drying chemicals such as organic solvents, lacquers, polishes and other agents, any abrasive substance contacting the hoof, and shoe nail holes, Repeatedly moving a horse having dry hooves to wet grounds or on to wet grass sets up a cycle which causes alternate swelling and contraction of the hoof wall leading to stress cracks.
Measures which might be regarded as remedial often exacerbate the problem. Application of lacquers and polishes in organic solvents to the hoof wall removes the lipid film and its beneficial effect. So rather than helping to prevent dry hoof they actually promote that condition.
Dry hoof causes a number of series problems for a horse: a brittle hoof may be difficult to shoe and does not hold a shoe well; the impact to the hoof when the hoof strikes the ground while running is not as efficiently dissipated by a brittle hoof which can lead to cracking of the hoof and lamness of the horse. These problems, if unattended, will eventually cause a great deal of pain and suffering to the horse as well as leaving it lame and potentially useless.
Prevention and correction of the "dry hoof" condition requires a composition and method which will:
1. Restore moisture lost by the hoof keratin, PA0 2. Simulate the moisture barrier properties of the periople, PA0 3. Maintain a non-sticky hoof surface PA0 4. Avoid use of materials that build up on the hoof surface.
This invention meets these requirements and is effective in correcting a dry hoof condition and thereafter maintaining the hoof in a healthy water-balanced condition.